In-Plane Strength and Stiffness of Cross-Laminated Timber Shear Walls

Shahria Alam,Thomas Tannert,Md Shahnewaz

doi:10.3390/buildings8080100

Abstract

The research presented herein investigated the in-plane performance of cross-laminated timber (CLT) shear walls for platform-type buildings under lateral loading. Finite element models of CLT connections (i.e., brackets, hold-downs and self-tapping screws) were developed in OpenSees and calibrated against experimental tests to represent the connections’ hysteresis behaviour under cyclic tension and shear loading. The results were incorporated into models of CLT single and coupled shear walls. The results in terms of peak displacement, peak load and energy dissipation were in good agreement when compared to full-scale shear wall tests. Subsequently, a parametric study of 56 single and 40 coupled CLT shear walls was conducted with varying numbers and types of connectors (wall-to-floor and wall-to-wall) for evaluating their seismic performance. It was found that the strength, stiffness and energy dissipation of the single and coupled CLT shear walls increased with an increase in the number of connectors. Single shear walls with hold-downs and brackets performed better under seismic loading compared to walls with brackets only. Similarly, coupled shear walls with four hold-downs performed better compared to walls with two hold-downs. Finally, ductility of coupled shear walls was found to be 31% higher compared to that of single shear walls. The findings from this research are useful for engineers to efficiently design CLT shear walls in platform-type construction.

Highlights

The Finite Element Analyses (FEA) models of connections were calibrated using the test results presented by Gavric et al [12,13] and Schneider et al [14]
The Pinching4 model accurately captured the load-deformation hysteresis behaviour, including the backbone curves of cross-laminated timber (CLT) connections, with the hysteresis loops showing that the FEA line up with the test results in most of the cycles
The present study evaluated the behaviour of single and coupled CLT shear walls under lateral loading

Summary

Introduction

New mass timber products such as laminated veneer lumber (LVL) cross-laminated timber (CLT) [1], efficient connectors such as long self-tapping screws (STS) [2,3], innovative ductile connections [4,5], and pre-fabrication [6] have created an opportunity to build mid- to high-rise timber buildings. CLT panels consist of several layers of boards stacked crosswise and glued together. A CLT element usually has three to nine glued layers of boards placed orthogonally to each other (90◦ ) to form a solid panel [7]. Use of CLT for wall and floor panels offers many advantages: The cross-lamination itself provides improved dimensional stability and thermal insulation, and a fairly good response in case of fire, which are added benefits resulting from CLT’s massiveness [8]

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Results

Conclusion